ChIP was performed on larval discs and brains from 3rd instar larvae. The method is as described in Langlais et al. (2012) with the following changes. Action buffer was replaced with: 50mM Tris/HCl pH8.0, 50mM NaCl, 1mM EDTA, 0.1%SDS, 1% Triton X-100, 0.1% deoxycholate plus Roche Complete Protease Inhibitor Cocktail (EDTA free). Sonication was carried out using a Q Sonica (Model Q800R3), at 70% amplitude with 30 seconds on, 30 seconds off for a total time of 22 minutes. Protein A SepharoseTM Fast Flow (Cytiva), was used in place of the Protein G agarose/salmon sperm DNA beads. ChIP was carried out with 1:100 dilutions of anti-Ph (Buchenau et al. 1998), anti-E(z) (Brown et al., 2018), anti-Spps (Brown and Kassis, 2010), anti-Pho (Brown et al., 2003), anti-Sfmbt (Erokhin et al. 2015), anti-H3K27me3 (Millipore 17-622) or (Invitrogen MA5-11198). DNA concentrations of ChIP samples were measured using a Qubit 3.0 fluorimeter (Invitrogen). 1.5ng of starting material was used to prepare each library. Libraries samples were made using either (H3K27me3 samples only), the NEBNext UltraTM II DNA library preparation kit and single index kit (New England Biolabs), or (all other samples), the Thruplex DNA-seq and single index kits (Takara). Libraries were made following the manufacturer's directions.